The present invention relates to a water and oil repellent having high resistance to laundering and dry cleaning.
Hitherto, it is known that polymers of fluoroalkyl group-containing polymerizable compounds with or without other polymerizable compounds such as acrylic esters, methacrylic esters, chloroprene, vinyl chloride, maleic esters and vinyl ethers are useful as water and oil repellents. It is also known that the choice of hydroxyl group-containing acrylic or methacrylic esters as the compounds to be copolymerized with the fluoroalkyl group-containing polymerizable compounds can enhance the resistance of the resulting polymers to laundering and dry cleaning (cf. Japanese Patent Publication (examined) No. 3798/1975). However, the enhancement of the resistance to laundering and dry cleaning in the latter case is not satisfactorily high. Although the use of some other polymerizable compounds instead of the hydroxyl group-containing acrylic or methacrylic esters has been proposed, the enhancement is still insufficient.
As the result of an extensive study, it has now been found that copolymers comprising units of at least one fluoroalkyl group-containing polymerizable compound and at least one of 2-hydroxy-3-chloropropyl acrylate or methacrylate of the formula: EQU CH.sub.2 .dbd.CRCOOCH.sub.2 CH(OH)CH.sub.2 Cl
wherein R is hydrogen or methyl show excellent water and oil repellency with high resistance to laundering and dry cleaning. Advantageously, they exhibit high stability in water and good solubility into organic solvents.
The reason why the said copolymers show high resistance to laundering and dry cleaning is still not certain. Since, however, their effect onto cellulose fibers having many active hydrogens is much more remarkable than that onto polyester fibers, polyamide fibers, etc., it is presumed that a chemical bonding is produced between the hydroxyl groups or the terminal chlorine atoms and the materials to be treated.
According to the present invention, there is provided a water and oil repellent consisting essentially of a copolymer comprising at least one of fluoroalkyl group-containing polymerizable compounds and at least one of 2-hydroxy-3-chloropropyl acrylate and 2-hydroxy-3-chloropropyl methacrylate. The content of the units of 2-hydroxy-3-chloropropyl acrylate and/or of 2-hydroxy-3-chloropropyl methacrylate in the copolymer may be usually from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight. When the content is less than 0.1% by weight, a sufficient effect in enhancement of the resistance to laundering and dry cleaning will not be produced. When the content is more than 10% by weight, the water and oil repellency is much lowered.
Examples of the fluoroalkyl group-containing polymerizable compounds are C.sub.3 -C.sub.15, preferably C.sub.5 -C.sub.10, perfluoroalkyl group-containing acrylates and methacrylates of the formula: EQU R.sub.f BOCOCR.dbd.CH.sub.2
wherein R.sub.f is C.sub.3 -C.sub.15 perfluoroalkyl, B is (CH.sub.2).sub.m (in which m is an integer of 2 to 11), ##STR1## (in which R' is methyl, ethyl or propyl) or SO.sub.2 N(R")(CH.sub.2).sub.l (in which R" is methyl, ethyl or propyl and l is an integer of 2 to 6) and R is as defined above, of which specific examples are as follows: CF.sub.3 (CF.sub.2).sub.7 (CH.sub.2).sub.11 OCOCH.dbd.CH.sub.2, CF.sub.3 (CF.sub.2).sub.6 CH.sub.2 OCOC(CH.sub.3).dbd.CH.sub.2, (CF.sub.3).sub.2 CF(CF.sub.2).sub.8 (CH.sub.2).sub.2 OCOCH.dbd.CH.sub.2, CF.sub.3 (CF.sub.2).sub.6 (CH.sub.2).sub.2 OCOC(CH.sub.3).dbd.CH.sub.2, CF.sub.3 (CF.sub.2).sub.6 (CH.sub.2).sub.2 OCOCH.dbd.CH.sub.2, CF.sub.3 (CF.sub.2).sub.7 SO.sub.2 N(CH.sub.3)(CH.sub.2).sub.2 OCOCH.dbd.CH.sub.2, CF.sub.3 (CF.sub.2).sub.7 SO.sub.2 N(C.sub.2 H.sub.5)(CH.sub.2).sub.2 OCOC(CH.sub.3).dbd.CH.sub.2, (CF.sub.3).sub.2 CF(CF.sub.2).sub.6 -CH.sub.2 CH(OCOCH.sub.3)CH.sub.2 OCOC(CH.sub.3).dbd.CH.sub.2 and (CF.sub.3).sub.2 CF(CF.sub.2).sub.6 CH.sub. 2 CH(OH)-CH.sub.2 OCOCH.dbd.CH.sub.2. These fluoroalkyl group-containing acrylates and/or methacrylates are usually employed so as to be contained in an amount of not less than 25% by weight on the basis of the weight of the copolymer.
In addition to the said two essential components, the copolymers may comprise optionally units of any other polymerizable compound(s) having no fluoroalkyl group, of which examples are ethylene, vinyl chloride, vinylidene halide, styrene, acrylic acid and its alkyl esters, methacrylic acid and its alkyl esters, benzyl methacrylate, cyclohexyl methacrylate, vinyl alkyl ketone, vinyl alkyl ether, butadiene, isoprene, chloroprene, maleic acid, etc., for the purpose of providing the resulting copolymers with improved physical properties such as high solubility and good water proofing. For instance, the use of stearyl acrylate or methacrylate as such other polymerizable compound(s) having no fluoroalkyl group is effective in enhancing water repellency, elasticity, gum-up inhibiting property to rolls and solubility in organic solvents. In this case, the most preferable is the copolymer comprising units of the fluoroalkyl group-containing polymerizable compound, 2-hydroxy-3-chloropropyl acrylate or methacrylate and stearyl acrylate or methacrylate in contents of not less than 25% by weight, from 0.1 to 10% by weight (preferably from 0.2 to 5% by weight) and from 5 to 74.9% by weight, respectively.
For production of the copolymers of the invention, various conventional polymerization modes and conditions can be adopted. Any of bulk polymerization, solution polymerization, emulsion polymerization, radiation polymerization, etc. may be employed.
One of typical polymerization procedures comprises emulsifying a mixture of the monomeric components to be copolymerized in the presence of a surfactant and subjecting the resultant emulsion to polymerization while stirring. To the reaction system, a polymerization initiator such as peroxides, azo compounds and persulfates is added. As the surfactant, any one chosen from anionic, cationic and non-ionic surface active agents can be used, and a mixture of a cationic surfactant and a non-ionic surfactant is preferably employed.
Another typical polymerization procedure comprises dissolving the monomeric components to be copolymerized into an appropriate organic solvent and subjecting the resultant solution to polymerization in the presence of a polymerization initiation source such as a peroxide or an azo compound soluble in the organic solvent or ionizing irradiation.
The thus prepared copolymers may be used as water and oil repellents in any conventional form such as emulsion, solution and aerosol.